Although perinatal transmission is the dominant route of HIV-1 infection in children, less than one-third of all babies acquire their mother's infection. In children who do become infected, the clinical course varies from indolent to rapidly fatal. An understanding of the factors contributing to these variations can lead to the development of management strategies that may diminish the spread and severity of this disease. Since most HIV-1 infected women in the U.S. are drug users, factors affecting a pregnant drug user's health should be examined as predictors of the clinical outcome of the child. This project will investigate the influence of maternal characteristics during pregnancy on the child's risk of infection and clinical course. The contribution of post-natal care patterns for these children to the child's clinical course will also be examined. The study will focus particularly on the impact of factors that can be modified such as methadone treatment and level of prenatal care for pregnant, HIV-infected women. A retrospective cohort of nearly 1100 New York State Medicaid-enrolled women who delivered 1330 babies in 1985-90 will be linked to their children's records for analysis. Maternal factors found in the Medicaid cohort to predict the child's risk of developing AIDS will also be tested as predictors of HIV transmission risk on a prospective cohort of 180 HIV-1 infected women and their offspring. This group has been followed at New York University/Bellevue Medical Center since 1986. The study aims are: 1. For children born to HIV-infected, NYS Medicaid-enrolled women, to determine the influence of maternal clinical characteristics and prenatal care as well as the child's perinatal and postnatal medical care on the child's risk of AIDS, clinical course, and life expectancy. Factors to be explored include the following: a) continuity of prenatal care; b) prenatal methadone treatment and psychiatric care; c) history of maternal untreated drug abuse; d) maternal stage of disease and clinical complications; e) type of delivery; f) child's pattern of ambulatory care; g) mother's and child's anti-retroviral and prophylactic drug treatment; and h) child's placement in foster care. 2. For children born to HIV-infected women in the prospective NYU/Bellevue cohort, to examine how predictors from aim #1 and measures such as maternal immune status during pregnancy in the prospective cohort affect the child's risk of becoming HIV-infected and, for the HIV-infected child, modify rate of disease progression to symptomatic disease and to death. This study is designed to identify health care delivery and clinical factors that may be modified to reduce the risk of infection and rate of disease progression in the child of an HIV-infected woman. This information is of central importance for planning services and delivering health care for this growing population.